Processing Method Research Of Seismic Data In Complex Area In Naimanqi Rag Of Inner Mongolia

Along with exploration and development level of Liaohe peripheral basin Areas heightened, oil gas exploration of complex area becomes the major way to enlarge the oil gas production of Liaohe Oilfield. It is proved through investigation that there are fifty sags with the area about 45,000 km2 in Liaohe peripheral basin, including Naimanqi sag, Lujiabao sag,Qianjiadian sag, Longwantong sag,Zhangqiang sag, Fuxin sag and Yuanbaoshan sags etc. However, geologic conditions in Naimanqi sag is very complex ,such as crushed structure, complex fracture, low S/N, no good reflecting in mid-deep layer, in-equable energy, bad absorption attenuation, complex types and strong noise, bad statics condition, narrow frequency bandwidth, etc., which lead to difficult seismic datum processing.The study of processing methods is carried out according to seismic datum characteristics in Naimanqi sag area, the studies are statics methods in complex area, high fidelity noise suppression, amplitude-preserved data processing methods, improving S/N, wavelet-consistent processing methods, and migration imaging method, etc. The purpose of studying is to form seismic datum processing theory and method of science which is suitable for low S/N area, to form one set of datum processing procedure for exploration in Inner Mongolia area, and to provide highly reliable datum for oil gas exploration study.In order to form the data processing method and procedure, the basic seismic data processing theory in low S/N area is studied, including the seismic wave propagation rules and attenuation rules in the medium of underground, and noise and resolution.Suitable data processing method is formed after studied ample surface-deep layer geologic settings and acquisition datum characteristics (inclusive of interference wave, S/N, frequency, energy).It is proved that assemble statics methods can solve the statics problem in Naimanqi area through the comparative study of three types statics method's characteristics and theory (including field statics, refraction wave statics and residual statics) and the application study of investigating and setting up surface layer model, choosing datum level, multi-iteration refraction wave statics and residual statics.After studying the pressing method of coherent noise and random noise, the conclusion is that regional filtering, multi-domain noise suppression, DMO suppressing slope reference wave, predictive de-convolution, multiple reflection suppression, F-X de-convolution, and maximum entropy superposition method are suitable for interference wave suppression in low S/N area of Naimanqi area. The studies of wavelet-consistent processing methods are including amplitude restoration and compensation for spherical divergence and geometrical divergence, surface consistent amplitude compensation, combination de-convolution method, frequency spectrum widening method, the result is that wavelet-consistent strengthening, improving S/N and frequency spectrum widening.The studies of complex structure migration imagine technique comprise building appropriate stack velocity field and migration velocity field (DMO velocity field), choosing appropriate migration method (wave equation migration), and post-stack noise suppression.Productive practice shows that this method has achieved obvious effect in raising processed seismic datum quality, and created a new thought for data processing method in complex area. It will make new contribution to discovering more oil-gas fields in complex area.